Polyunsaturated fatty acids (PUFA) are extensively studied in maternal and infant nutrition in the developed world, but studies in the developing world are scarce. We previously conducted an initial pilot study on the relationship of plasma phospholipid (PL) PUFA and birth parameters, which provided evidence that docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA) but not arachidonic acid (ARA) status were related to positive outcomes. We propose to conduct a well-controlled small, self-contained follow-up observational study of the relationship between PUFA and birth outcomes in a population of urban poor in which low birth weight (LBW) and prematurity rates are highly prevalent. Our primary hypothesis is Newborn and/or maternal plasma phospholipid long chain polyunsaturated fatty acid status are associated with birthweight and gestational age at birth in a population of low and middle income families in urban India. Newborn blood will be collected for PL fatty acid analysis and measured concentrations will be compared to anthropometric parameters and gestational length. Our secondary hypothesis is: Dietary and socioeconomic variables predict neonatal plasma PL polyunsaturated fatty acid status. Diet during pregnancy will be assessed with a food frequency questionnaires validated previously for this population. Socioeconomic status will be assessed as well. Fatty acid outcomes will be compared with these data. We also include the research question: Are the PUFA in specific plasma phospholipid molecular species better associated with growth than total plasma PUFA? We will analyze total plasma phospholipid molecular species according to mass spectrometry-based lipidomic methods in place in the US laboratory for exploratory purposes. The purpose is to probe, for instance, whether the concentration of specific molecular species (e.g. 18:0(sn-1),22:6(sn-2)phosphatidyl choline or 18:0(sn-1),22:6(sn-2) phosphatidylethanolamine) is better correlated to positive birth outcomes than plasma total PL 22:6 concentrations. The overall plan capitalizes on strengths of the Indian collaborator's experience and resources for maternal and infant research in the target population, and the US collaborator's experience in lipid nutrition and in lipid analysis, and provides a platform for state-of-the-art technology transfer. The public health importance is to clearly establish whether LCPUFA nutriture is related to birth outcomes in pregnancies of those who are marginally nourished. Positive results would justify an intervention studies to include LCPUFA in the diets of pregnant women in developed and developing countries.